The Art
of lossless
image compression
vol. 15

Here are the results of 10 tests performed in November-December 1999
to compare lossless compression of True Color (24-bit) images
by HP Labs' software implementation of JPEG-LS,
by popular PkZip, 7Zip, Boa, BMF, UHIC,
by archivers with _special_ algorithms for 24-bit images:
Eri32,ArHanGeL,Ufa32,777,ESP,Rkive,RKim,RK,UHarc,Imp,RAR,WinRAR,
and results on same images of the famous PNG algorithm and format
created by PngCrush, Display 1.89a, SEA 1.3, Image Alchemy 1.10
See Archive Comparison Test by Jeff Gilchrist for more details:
http://act.by.net/
If anybody wants to start or continue such tests,
or can suggest some other sets of images, or other compression programs,
(not sources or algorithm descriptions, programs for DOS or Windows only)
or knows we have missed something important,
(some new fantastic technology, an algorithm or even a program capable
of lossless compression of up to 1000:1 and lossy compression of
up to 10000:1 , we hear about it from time to time since our XTs)
please let us know immediately: ratush@srsc-gw.sscc.ru Thank you!

[[3]] Details

are no longer put to this main text
(816 lines reporting 5757 results on 303 files in 10 sets),
but can be found in FULL version with DETAILS.DAT and *.BAT
at http://geocities.com/SiliconValley/Bay/1995/artest15.zip
or http://artest1.tripod.com/artest15.zip
1,2,3,4,9 image sets were taken from ftp://ipl.rpi.edu/pub/image/ and /image2/
converted from Sun Raster format to Windows Bitmap,
(this conversion changes image headers only, 32 bytes
are replaced by 54 bytes, but image data is not modified)
This site ipl.rpi.edu is described in comp.copression FAQ by Jean-loup Gailly,
in 29 lines of "Subject: [55] Where can I find Lenna and other images?"
Eight images in the 5th set are from the famous Waterloo Color Set,
( losslessly compressed with Eri32 4.5fre to 2,894,045 bytes,
it can be found at http://geocities.com/eri32 )
6,7,8th image sets are from ftp://download.intel.com/pressroom/images/
10th set was downloaded from ftp://ftp.kodak.com/www/images/dental/
They were converted from TIFF format to Windows Bitmap.
Some images were slightly renamed. See DETAILS.DAT from artest15.zip for more
details. Some new images (from download.intel.com ) were not added yet.

What's new:

9 new programs were tested: ArHanGeL 1.40a2, Eri32 4.5fre, NK 99nov, RK 1.02a1,
PngCrush 1.1.8, Imp 1.10b5 (both DOS and Windows95/98/NT versions),
WinRAR 2.60, RAR32 for Dos and OS/2 2.60 .
NK is new image compressor with good compression ratio and time.
RK 1.02a1 with -mx1 was only 0.42% worser than RK 1.02a1 with -mx2
(304355092/303087960) and only 0.0006% worser than RK 1.01a1 with -mx1
(304355092/304353168).
PngCrush worked about 3 hours with -q switch , and about 64 hours with -brute .
WinRAR and RAR32 were compressing files to exactly same sizes,
but RAR32 was slower, as a rule.
33 new images appeared at ftp://download.intel.com/pressroom/images/ ,
they were already downloded, converted to .BMP, converted to .BMF,
and written to CDROM, but will be added to 6th, 7th and 8th sets later.
Three lossless JPEG programs mentioned in comp.compression FAQ -
> [15] Where can I get image compression programs?
> ftp://havefun.stanford.edu/pub/jpeg/JPEGv1.2.1.tar.Z (has lossless mode)
> ftp://ftp.cs.cornell.edu/pub/multimed/ljpg.tar.Z (lossless jpeg)
> http://idt.net/~dclunie/jpegls.html (lossless jpeg by David Clunie)
were not tested at all: no executables were found in these packages:
C sources only, and other interesting texts
(readme files, copyright and portability notices, test images, etc.)
The third link reports that
> It only handles one component (ie. grayscale images) for now.
while the forth desirable link from that section [15]
> ppm2pz: (lossless 24-bit image compression)
> http://www.jyu.fi/~kuru/compression.html
seems to be not valid (since 1997, by the way).

Some WARNINGS again:

ESP 1.92 has some bugs and was unable to correctly uncompress
some test images: they are (re)named in our tests as
AYMAR,GELSNGR,NACHTSH,OTELLIN,VADASZ,YASSO,YU1,
DP08189,DP2179D,L217C-3,CONCEP3,PS09157,V42798C.
ESP doesn't even report something like "CRC fails"...as if everything is OK.
Rkive 1.92b1 failed to losslessly uncompress most images
from 6th, 7th and 8th tests, and also Clegg, Frymire, Serrano from 5th.
It reports
ERROR: File fails CRC check!.
Archive failed integrity check.
RKim 1.03 failed to compress 3 images (AIRPLANE,GIRL3,SPLASH), and to extract
some images compressed with "cx" (CBARRETT,CHOU,GELSING2,DP011199,SP011199,
ED50799B,ED50799E,CONCEPT4,VC42798C,LIDOCAN1,LIDOCARP,RAPIDACC,COULSON).
RK 1.02a1 fails to extract set of two exactly-same bitmap files:
For example, "copy kodak01.bmp kodak01a.bmp",
and try "RK -mf1 Z kodak01*.bmp" , "RK -i Z"
The same happens if you try RK with any of -mx1, -mx2, -mx3, -mf1, -mf2, -mf3
ERROR 303: CRC check failed.
The LATEST RELEASE, and twelve previous versions of these tests can be found at
http://geocities.com/SiliconValley/Bay/1995/http://artest1.tripod.com/